Wetsuits and buoyancy

[marcbeaudry]

I'm curious to know what value of buoyancy is normally attributed to a wet suit?
i'm sure it's relative to the size and style (two piece one piece) of the suit and the thickness .
what a good rule of thumb for determining close weight requirements before getting into the water ?

thanks for your advice, opinions, bad jokes and experience !

marc

 

[TSandM]

You can determine the buoyancy of your exposure protection by putting it in a mesh bag and going to a pool, and seeing how much weight you have to attach to the bag to sink it. You can do a somewhat less accurate version of the same test by trying to sink the suit in a bathtub.

Buoyancy of suits can vary wildly, with thickness and age, from 25 pounds or so (or even more, if you're big or wearing multiple layers) to almost nothing for dive skins.

 

[herman]

Depends a lot on size, type and to some extent age of the wetsuit. Sinking it in a pool or other protected place is your best bet. I don't use a bag or any kind of container, it has the potential to trap too much air. I just open up the wetsuit and start placing weights on it, balancing it as best as I can, until it sinks. As an example, I was checking a vintage 1/4 beavertail top the other week. It required 8 lbs to sink

 

[lowviz]

I'm curious to know what value of buoyancy is normally attributed to a wet suit?
i'm sure it's relative to the size and style (two piece one piece) of the suit and the thickness .
what a good rule of thumb for determining close weight requirements before getting into the water ?

thanks for your advice, opinions, bad jokes and experience !

marc

Sounds to me like you are just trying to get close before your pool session. You will determine your proper weighting in the pool with about 500psi in your tank. Your BCD, gear, and even your body style play a big part in weighting. Did your instructor give you a guess for your weight belt or are you going in cold and looking for advice? (If I'm overthinking this, you already got your answer in earlier posts.)

 

[LeadTurn_SD]

....what a good rule of thumb for determining close weight requirements before getting into the water ?

thanks for your advice, opinions, bad jokes and experience !

marc

TS&M had a good suggestion to determine an accurate buoyancy for your suit.

You could also do the same test while wearing the suit : Get in the pool with wetsuit on, stand in chest deep water, lift you feet, then add weights to a mesh bag that you hold until you are neutral (float at eye level holding a normal breath). This establishes the buoyancy of you and your suit.

For what they are worth, here are a couple "Rules of Thumb":

1.) Approx. 3 lbs buoyancy per mm of wetsuit thickness; so for example, by this estimate an "average" 3mm suit would have around 9lb of buoyancy, a 7mm suit a bit over 20 lbs....

2.) Approx. 10% of your body weight for a 7mm suit....

But these gross approximations do not take into consideration suit size, body composition, etc. So they may turn out to be good "ballpark" starting points, or "not even close"

 

[marcbeaudry]

hello all -
thanks for the replies.I've done my open water cert.
already, but my buoyancy wasnt correct despite the best efforts
of my instructor. I wore a 3XL - 7mm one piece suit with a 7mm vest and hood
overtop (new Bare Elastek) and also recently purchased a second bare 3mm full 1piece suit
for warmer climes -(both have had an additional 3inches added to the leg length)
i weigh 240lbs.
at the time of my open water cert (which although being in COLD water ,it went super well !)
i dove with too little weight on my first three dives 36lbs, and too much on my last, 46lbs.
so it would stand to reason that somewhere between 36 and 46 will be ideal for the 7mm full suit and vest combo - but I felt it was somewhat arbitrary and wondered what if any math
there was behind it. pool test seem to be the most conclusive - essentialy it's the identification
of the volume/displacement of the suit.
interesting - thank you very kindly for all of your responses. it's very much
appreciated !
Marc

 

[lowviz]

... I've done my open water cert.
already, but my buoyancy wasnt correct despite the best efforts
of my instructor. ...

Try relaxing on the surface while breathing from your reg. Drop just below the surface a few times until you lose the urge to keep your head above water. Mind those fins. Next, focus on staying still underwater and keeping your breathing regular. Re-do the weighting procedure.

The amount of air that you allow to remain in your lungs between breaths makes a big difference in your buoyancy. This is very useful for both temporary and minor buoyancy adjustments underwater.

 

[meesier42]

your probably not accounting for the newbie weight, most new divers are not what I would call relaxed in the water. For many reasons this seems to add anything from 4-10 lbs of extra lead. As you start diving more, you will find with everything else the same, you need to dump more and more lead.

Best thing to do it get close for your first couple of dives and keep good logs, write down what you suit your wore and how much wieght, then at your safety stop think about it, are you neutral? light? heavy? how is your trim? Then you will be able to fine tune it, not to mention recall what it took the last time you wore that suit.

 

[Pullmyfinger]

For what they are worth, here are a couple "Rules of Thumb":

1.) Approx. 3 lbs buoyancy per mm of wetsuit thickness; so for example, by this estimate an "average" 3mm suit would have around 9lb of buoyancy, a 7mm suit a bit over 20 lbs....

Your rule of thumb for 3mm suits might be too much. 9 lbs. is probably too high of an estimate for a 3mm suit.

It's probably best to check it yourself.

-Mitch

 

[MagicChicken]

newbie weight

this is soooooo true